IVGCVSW-4246 Clean build profiling with -Wextra

Change-Id: Ieab870fa2194075433a0a26abdb13f69e1fbaaae
Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
diff --git a/src/profiling/FileOnlyProfilingConnection.cpp b/src/profiling/FileOnlyProfilingConnection.cpp
index 004e27d..7586261 100644
--- a/src/profiling/FileOnlyProfilingConnection.cpp
+++ b/src/profiling/FileOnlyProfilingConnection.cpp
@@ -40,6 +40,8 @@
 
 bool FileOnlyProfilingConnection::WaitForStreamMeta(const unsigned char* buffer, uint32_t length)
 {
+    boost::ignore_unused(length);
+
     // The first word, stream_metadata_identifer, should always be 0.
     if (ToUint32(buffer, TargetEndianness::BeWire) != 0)
     {